Secondary battery



July 14, 1936.

H. DE MARTS ET Al.

SECONDARY BATTERY Filed Dec. 4, 1935 /z/Ez 2 oooooooooooo WML Patented July 14, 1936 UNITED f'S"l`ATES, P i j snooNnARr rn'r'rnar "Horace De Martis and Sydney .lames Clark, New

Malden, England,A assignors to The Young Acv cumulator Company (1929) .Limitedtv New sheet'in its fully or partly vulcanized state is 2, this elevation showing the relative positionsof 1,5 conjoined by vulcanization to a sheet of porous the sheets l and 2 with' respect to the electrode ebonite. The porous ebonite has the effect of 3 and the manner in`whiclithecompositefsheets preventing the passage of material that disare sealed together `andthewhole is cushionecly""f]v integrates from the electrode Whilst freely per-- Fig. 4 is a Vside'elevation-cfa comp'ositeisheetfimitting of the ow of electrolyte; and the permodied with respect to Fig;v4 1 in' thatthefp dus Vf2 forated ebonite, apart from its function of prosheet V2 is smaller thanftheprfortdslieetl gf vidlng a key for' the .sealing medium, gives in order to provide a perforated margir'll along strength and flexibility to the porous ebonite. the vertical sidesandlthe bottom ofthe"com'positivi The size of the porous ebonite is preferably sheet; "i

smaller than that of they perforated ebonite to Fig. 5 is a sectional elevation on a larger scale '2 expose marginal portions of perforated ebonite.' of part of an envelope constructed frorn-sheets f In this arrangement the sealing medium beas that illustrated in Fig. 4,'sai`d` 'envelopecon comes locked to the said margins in that it is taining an electrode3;

' able to flow round both faces thereof and flow into Fig. 6 illustrates a piecev of lrubber strip s'ed` and unite in the perforations or slots. for uniting or sealing the composite sheetsando v L The arrangement and sealing of the sheets for forming the cushion;'

according to the invention adds to the mechani- Fig. 7 is a plan view'of the lower part" of a cal strength of the whole envelope or separator mould for forming the said envelope; and

and enables to be made a satisfactory sealing Fig. 8 is a sectional elevation of the said mould g5 40 state are conjoined by vulcanization to the sheets 40 2 to 3%'.v This mixture provides a cushion hav- 2 of porous ebonite. y f ing the requiredfdegree of resiliency Ato. minimize To make one form of envelope according to the mechanical shocks and effectively unites the invention a composite sheet (Fig. 1) i slightly sheets comprising thel envelope. 'l smaller thanthe recess 5 inthe lower part of r'Ilheenvelopes maybe separated in the battery the mould is laid, porous side downwards, in the r l .v i 4o container 1n any suitable manner. For example,` said recess so that amargln l 1s provided aroundl the container may vbe grooved'and the envelopes two sides` and an endof the sheet. The plate tted into "the grooves, vor the outer faces of the 3 is then placed on theperforated sheet in the envelopes'may be ribbedand the ribsof adjacent mould. The face of this plate is smaller than envelopes made toco'ntact `with each other. In the composite sheet so that ltheperforated sheet 5U any case the arrangement is' such that the-outer is left with margins @exposed Within the margins 1 side yfeinesof the cushionsere'flushwith the outer l, 'the connecting tongue of the said vplate being side'faces oftheirenve'lopes so' that the' necessary i received in a recess k9 vin themouidl part t. VA- ilow of the. electrolyte from* bottoniy to top' of second composite sheet similar tothe first is then the battery'isnotiprevented'nor hindered. 55

Malden, England, a British company Application December 4l, 1935, Serial No. 52,900 v i In Great I tritaink December l2, 1934i l eeiaims. (el. isc- 147) This invention relates to improvements in and pertaining tosecondary' batteries and refers, more particularly, to an improved envelope for the electrodes .or plates thereof and to a method of manufacturing the said envelopes.

An envelope'according tothe present invention consists oftwo spaced sheets of perforated materialrwhich are unitedV to each other along marginal portions by means of soft rubber which keys in the perforations inthemargins and provides a resilient surround for the assembly comprisecl by the envelope and plate.

In the preferred form -ofl the invention the perforated sheets 'are'made of ebonite. Each which does not protrude beyond the total thickness of the envelope. Y

The s oft rubber consists of any suitable mixture, -for example, a .rubber-sulphur, mixture having a total'sulphur content of approximately The invention will now be described with'reference to the accompanying drawing wherein:A

Fig. 1a shows an end elevation 'and a Fig. 1 shows a'front view of a sheet l ofv perforated ebonite joined by vulcanizing to a sheet 2 of porous ebonite, part ofthe perforated ebonite Cil f being broken away in the front elevation in order to expose the porous sheet;` .f

Fig. 2 is a perspective view of an envelope con structed according to the present invention from 10 composite sheets as that illustrated in Fig'. "l,

the envelope containing a battery electrod'e'it;

Fig. 3 is as'ectional elevation, on an enlargedf scale, of apart of the assembly illustrated `in' Fig. 7

and its top plate in readiness for moulding an i envelope according to the present invention containing the electrode 3. l

The sheets l in their fully or partly vulcanized laid perforated side downwards, on the plate t.

In this manner marginal portions i' corresponding to the margins I are provided on the perforated underface of the second composite sheet.

At suitable stages during the procedure above set forth, or at the end of this procedure, soft rubber strip I0 is forced with the aid of a suitable bladed tool into the U-shaped space comprising the margins 1.

The top plate I I of the mould, which plate is hinged to the part 5 at I2, is then lowered onto the said part 6 and the closed mould subjected to heat and pressure.

The plate I I has a false plate or block I3 on the underside of which is a U-shaped flange Il slidably fitting into a groove I5 of similar shape in the plate II. The groove I5 and the flange Il are so located that they coincide exactly with the margins 1.

The heat has the eect of softening and vulcanizing the strip III; and the pressure that of forcing the flange I5 to squeeze the soft rubber into the space between the margins 8 and I and into such perforations as lie within the margins. In this manner each composite sheet is sealed or united to the other along three of its edges. The rubber finds a key in the perforations in the margins 3 and l', whilst the rubber which remains in the space formed by the margins 1 provides a -surround III' around three sides of the envelope.

After the heat and pressure have been applied the mould is removed from the press and opened to permit of the removal of the envelope and plate 3, the false plate I3 being returned to its original position by means of compression springs I6 the action of which is limited by stop studs I1.

'Ihe strip I0 is composed of soft rubber of any suitable mixture, for example, a rubber having a total sulphur content of approximately 2 to 3% so as to remain resilient after vulcanization. In this manner the surround III' provides a cushion for the whole assembly and the soft rubber in the space between the margins l. 3' a cushion for the electrode besides uniting the two composite sheets.

Composite sheets such as that illustrated in Fig. 4 are made into envelopes in substantially the same manner as already described with reference toFigs. 1 to3and6to8. InthecaseofFigA, however, the soft rubber also spews around the margins 1 of the composite sheets and passes into the perforations in the margin where it units with rubber spewing into the space between the margins I. 8' (Fig. 5). In this manner the rubber is locked to the composite sheets and the whole assembly and the electrode are cushioned in the manner already described.

The sheet 2 illustrated in Fig. 4 is ribbed as shown at Il. The sheets 2 illustrated in Figs. 1, 2 and 3 are preferably ribbed in like manner and the moulds correspondingly shaped. 'I'he ribs provide spacers between adjacent envelopes arranged in a battery container. The sides of the soft rubber' are, however, ush with the outer faces of the perforated sheets so as not to seal or obstruct the bottoms of the spaces formed between the envelopes by the said ribs II.

If desired a plane upper plate may replace the plate II and the block I3.

'Ihe drawing shows perforations consisting of circular holes: the perforation may be of any suitable shape e. g., elongated (or slotted) openings or square holes.

What we claim is:-

1. An envelope for an electrode of a secondary battery. comprising two spaced sheets of perforated ebonite, a sheet of porous ebonite conjoined by vulcanization to the outer face of one of said perforated sheets and a second sheet of porous ebonite similarly conjoined to the outer face of the other perforated sheet, and a soft rubber surround, said surround keying in the perforations in the marginal portions of said perforated ebonite sheets to seal the sheets together and extending beyond the edges thereof to provide a cush- 10 ioning means around the envelope.

2. An envelope for an electrode of a secondary battery, comprising two spaced sheets of perforated ebonite, a sheet of porous ebonite conjoined by vulcanization to the outer face of one of said 15 perforated sheets and a second sheet of porous ebonite similarly conjoined to the outer face of the other perforated sheet, said porous ebonite sheets being smaller thansaid perforated sheets and located thereon to expose perforated mar- 20 ginal portions of said perforated sheets, and a soft rubber surround, said surround keying in the perforations in the marginal portions of the outer and inner faces of said perforated sheets.

3. An envelope for an electrode of a secondary 25 battery, comprising two spaced sheets of perforated ebonite, a sheet of porous ebonite conjoined by vulcanization to the outer face of one of said perforated sheets and a second sheet of porous ebonite similarly conjoined to the outer face of 30 the other perforated sheet, said porous ebonite sheets being smaller than said perforated sheets and located thereon to expose perforated marginal portions of said perforated sheets, and a soft rubber surround, said surround keying in the 35 perforations in the marginal portions of the outer and inner faces of said perforated sheets to seal said sheets together and extending beyond the edges thereof to provide a cushioning means.

4. An envelope for an electrode of a secondary battery, comprising two spaced sheets of perforated ebonite, a sheet of porous ebonite conjoined by vulcanization to the outer face of one of said perforated sheets and a second sheet of porous ebonite similarly conjoined to the outer 45 face of the other perforated sheet, said porous ebonite sheets being smaller than said perforated sheets and located thereon to expose perforated marginal portions of said perforated sheets, and a soft rubber surround, said surround keying in the perforations in the marginal portions of the outer and inner faces of said perforated sheets to seal said sheets together, extending beyond the edges thereof to provide a cushioning means, and having a thickness such that its side faces do not extend beyond the outer faces of the envelope.

5. A unit for use in a secondary battery comprising a plate electrode in an envelope according to claim 2, said surround providing a cushion 60 around said electrode as well as around said envelope.

6. An envelope for an electrode of a secondary battery, comprising two spaced sheets of perforated material, a sheet of porous material indivisibly united to the outer face of one of said perforated sheets, a second sheet of porous material indivisibly united to the outer face of the other of said perforated sheets, and a soft rubber surround keying the perforations in the mar- 70 ginal portions of said perforated sheets to seal the sheets together.

HORACE DE MARTIS. SYDNEY JAMES CLARK. 

